?>

# Department of Science, Math, & Technology

E = mcÂ˛
What would happen if you fell into a black hole and turned around?
Posted: Posted August 12th, 2018
Edited August 12th, 2018 by Louis De Pointe du Lac
 Although my understanding of this stuff is rudimentary I'm gonna speculate what I think would happen if you were to look back at the Universe after falling through the event horizon of a black hole. First lets say the black hole is big enough and the singularity and event horizon are far enough apart that you aren't spaghettified (pulled into a long taffy string) before entering. First of all the more warped space and time is the more time slows down. But in the case of a black hole that warp is infinite and therefore time stops. As long as you're in free fall you're weightless. So being crushing by infinite heaviness shouldn't be a problem. However it is my opinion that the terminal velocity of objects in free fall below the event horizon is equal to the speed of light. Any objects traveling (or falling) at the speed of light wouldn't experience time. Their journey to wherever would be instantaneous relative to them, even if it isn't relative to everything else. Therefore because time stops for objects below the event horizon of a black hole/objects falling at the speed of light it wouldn't matter if the time it took you to reach the singularity wasn't instantaneous. Relative to you it would be, since time has stopped for you. So basically you cross the event horizon and the next thing you know hello singularity and instant death! Another problem is that anything with mass cannot travel at the speed of light. Which means that anything falling at the speed of light can't have mass. Which means objects crossing the event horizon are probably instantly converted into pure energy. Which means you can't pass an event horizon and stay alive, singularity or not. So in both cases bad news. But setting all that aside suppose you could turn around and see the Universe after falling through a black hole. What would you see? Some believe you would see time itself end and the reason is simple. Like I said relative to you time has stopped. Which means from your point of you, you'd see all of time happen at once. That MIGHT mean you'd see all the visible light the Universe will ever produce from the point you entered the black hole to the death of the Universe flash at once. Bye bye eyeballs. But personally I don't think this is the case. At least not the "see time end" part. To say that seems to assume that black holes will exist forever. But they don't. Hawking radiation gradually whittles them away bit by bit until they disperse as radiation. This does take an extraordinary amount of time. Around 10 to the power of 76 years to 10 to the power of 100 years. More than enough time for the heat death of the Universe (where entropy evens out all the energy in the Universe until everything that gives off light and heat is uniformly spread out resulting in a black endless and very cold void of nothingness). Thus the "every light produced by the Universe from the point of entering the black hole until the end of the Universe (or at least the heat death of its energy)" still flies. So yea bye bye eyeballs. However once again inside the black hole time is instantaneous relative to you. So even though relative to the outside the black hole takes a phenomenal amount of time to die out, no time at all would pass for yourself. In summary I think you would see the lifespan of the black hole happen at once, NOT time itself. Meaning one moment you're at the event horizon and the next you're in the middle of a bunch of radiation and otherwise surrounded by a cold void of heat dead Universe. But of course in reality my hypothesis is this: One moment you are at the event horizon and the next moment you ARE the cloud of radiation that has escaped an either destroyed or naked singularity one googol years later.
settingsOptions
There are 4 Replies

The issue with event horizons is that black holes warp spacetime.. if you were past the event horizon you would cease to have any access to the rest of the Universe whatsoever as the black hole's singularity would be in all directions. That's also more the real reason why you can't escape.

Before that happened though, the singularity would be curving around your field of vision -- at some point the universe would shrink to a window and then a pinhole before disappearing altogether. It would be interesting to turn around during that process.

Black holes don't just warp space, but also time. Turning around you'd get to see the universe go really really fast, and although your vision would be warped, it would make a beautiful display. If you were careful and had a lot of energy and escaped at this point, a ridiculous amount of time would have passed since you first went to the black hole. Millions or billions of years. Good luck even finding home, much less your old species.

Personally, I think more interesting than a black hole is the concept of a naked singularity -- in this case a black hole is spinning rapidly, which produces two event horizons that shrink towards each other and eventually disappear, leaving behind a singularity that is directly observable.

Posted August 12th, 2018 by Xhin
Xhin
Nature is beautiful

The issue with event horizons is that black holes warp spacetime.. if you were past the event horizon you would cease to have any access to the rest of the Universe whatsoever as the black hole's singularity would be in all directions. That's also more the real reason why you can't escape.

Ah yes that's correct. I forgot about that part.

Before that happened though, the singularity would be curving around your field of vision -- at some point the universe would shrink to a window and then a pinhole before disappearing altogether. It would be interesting to turn around during that process.

The moment the Universe disappeared altogether would probably be the "cross the event horizon" point. After that you're falling at light speed and instantly (at least relative to you) meet the singularity and become part of the black hole itself, experiencing 10^76-to-100 years passing instantly (again relative to you).

Turning around you'd get to see the universe go really really fast, and although your vision would be warped, it would make a beautiful display. If you were careful and had a lot of energy and escaped at this point, a ridiculous amount of time would have passed since you first went to the black hole. Millions or billions of years. Good luck even finding home, much less your old species.

Yup as long as you could see the Universe, there would be hope of escape. But only after star-lifetimes worth of time had passed.

So it would probably be more accurate for me to say you'd see a rapidly aging and morphing Universe distort and shrink into a point. Then suddenly you're hawking radiation floating in a post-heat death void.

Personally, I think more interesting than a black hole is the concept of a naked singularity -- in this case a black hole is spinning rapidly, which produces two event horizons that shrink towards each other and eventually disappear, leaving behind a singularity that is directly observable

Spinning black holes are interesting. Since singularities are 1-dimensional they can't actually spin, so the only way relativity can account for a spinning black hole is by turning the singularity into what's called a "ringularity" meaning the 1-dimensional point is traveling in a circle creating a kind of 2-dimensional ring, thus twirling its event horizon around like a lasso. At least that's how I understand the concept.

Edited August 13th, 2018 by Louis De Pointe du Lac
Louis De Pointe du Lac
No love = No future

You’d become black?

Posted August 13th, 2018 by Brandy

You’d become black?

Everything's gonna be black one day!

Posted August 13th, 2018 by Louis De Pointe du Lac
Louis De Pointe du Lac
No love = No future
Reply to: What would happen if you fell into a black hole and turned around?